Door operating mechanism



May 2, 1939:

*ir-b v INVENTOR.

TTORNEY.

' vBY F. LICHTFELDT DOOR OPERATING MECHANISM May 2, 1939.

Filed July 12, 1937 4 sheets-sheet 2 i INVEN TOR. Eh-' mW/ffm? ATTORNEY.

May 2, 1939.v

F. LICHTFELDT DOOR OPERATING MECHANISM 4 Sheetsl-Sheet 3 Filed July l2, 1957 NN .www

l INVENTOR. Cif/fzf L ATTORNEY.

May 2, 1939. F. LlcHTFELDT DooR QPERATINGA MEcHANsM Filed July 12, 19:57 4 sheets-sheet 4 #A l .,/w\\\ f/ r f v wm, S1 L f N N S It :n.ll u N n mm NN. NN m mm QN Q NW .mm1 NI N. NN LR IIIIIIIII 1| IN VENTOR.

ATTORNEY.

Patented May 2, 1939 UNITED STATES PATENT orFleE 18 Claims.

This invention relates to door operating mechanism and is particularly directed to mechanism for operating garage doors.

Objects of this invention are to provide a garage door operating mechanism which is so made that the driver can open the doors by hand when he is leaving and by this operation store a suicient amount of energy in the mechanism as, for example, by lifting a relatively large weight, may thereafter drive his car from the garage and operate a trip mechanism through the medium, for example, of a pull cord to release the mechanism and allow the doors to automatically close Vunder the influence of the relatively large weight, the descending large weight preferably storing a portion of the energy in the mechanism byraising a relatively smaller weight, which remaining portion of the energy is utilized to subsequently open the doors so that upon returning the operator may operate the mechamsm to open the doors without leaving his car and may then drive into the garage.

Further objects are'to provide a construction in which means are provided for automatically temporarily locking the doors in open position until the trip mechanism is operated, in which means are provided for automatically closing and locking the doors closed, and in which means are provided for automatically unlocking the doors and opening them and again locking them in open position temporarily until released by the operator.

Further objects are to provide a construction in which the release mechanism may be operated from Ya pull cord, the mechanism being so arranged that a large amount of slack in the-cord is provided so that the operator'may grasp the cord as he drives from the garage, the slack allowing him to drive a sufficient vdistance vto clear the doors and the trip mechanism having a delayed action and closing only after the slack of the pull oord has been taken up, the construction providing `a slack take up rmechanism to quickly Withdraw the cord into the garage before the doors are automatically closed, suitable dash pot mechanism being provided to prevent shock particularly during the final portion of the 'opening motion of the doors.

Further objects are to provide a construction which is operated by the force of the automobile when the automobile is outside of the garage to release the mechanism and allow the doors to open, the construction being such that it is impossible for anunauthorized person to operate the mechanism by hand from the outside of the doors as a considerable amount of force, such as supplied by the automobile, is required for the automatic release of the doors, opening means however being provided, such as a key operated mechanism, so that the authorized operator may manually release the latch andropen the doors by hand from the outside. 7A further object of this invention is to provide a construction so that the releasing mechanism may be operated bythe automobile itself from the outside of the garage, the mechanism being so constructed that the amount of force required to release the mechanism may be adjusted to any desired value.

Further objects are to provide a construction which though mechanically operated and having the several functions hereinabove enumerated, is nevertheless relatively simple and may be cheaply constructed.

An embodiment' of the invention is shown in the accompanying drawings, in which:

Figure 1 is a fragmentary side elevation of the device.

Figure 2 is a side elevation, partly in section and partly broken away, showing the main carriage, the trip mechanism and the associated parts in door closed position.

Figure '3 is a plan view of the structure shown in Figure 2. f l Figure 4 is a fragmentary View corresponding to Figure 1 and showing the parts in door open Figure 10 is a fragmentary sectional view on the line lil- Ill of Figure 8.

Figure 11 is a fragmentary view, partly in section, of the automobile'operated release means.

Figure l2 is a fragmentary plan view of the mechanism showing the ldoors in closed position in full lines, and in open position in dotted lines.

Figure 13 is a sectional view on the line l3-l'3 of Figure 2.

Figure 14 is a detail, partly in section, showing the slack take up means for'the pull cord.

The major portion of the mechanism is-carried by a pair of guide rails or tracks I which are supported adjacent their front endfby means of a bracket 2 secured to the stationary Yframe 3 adjacent the doors 4. These rails may. conveniently have reversely turned portions I which are secured by means of a bolt 5 to the bracket, the bracket having down turned fingers 6 on opposite sides of the rails to assist in positioning the rails. If desired, the bolt may have a square portion located between the rails, as indicated in Figure 3.

The rear portions of the rails are supported by means of the hanger member formed of the strap metal loopV 1, see Figures l, 2, 3 and 13, which is suspended by means of the wire 8 from the upper portion of the garage, see Figure 2.

' This support has a lower flat bottom portion serving as a spacer therefor.

- the rails on their outer sides, as shown in Figure 13. This construction allows lateral adjustment of the rear portion of the guide rails to insure the correct adjustment of the parts. The bracket I2v is additionally secured to the rails I by means of the bolt I2, see Figures 2 and 3. Y

A main carriage is slidably mounted on the guide rails or tracks and includes a bolt or rod member I6 which extends vertically through an upper sleeve I 'I and a lower sleeve I8. The carriage also includes an upper and a'lower pl-ate I 9 and 2l! positioned on opposite sides of the guide rails and having the bolt I6 passing therethrough.

The upper plate I9 preferably has downwardly turnedV side flanges located on opposite sides of the rails.

The carriage also includes a front latching member ZI and a rear latching member 22. VThe upper sleeve I1 is connected with one' of the doors by means of the operating rod'or link 23 and the lower sleeve I8 is connected by means of theoperating rod or link 24 with the other door, the rods'being adjustableras to length, as indicated in Figure 12.

being formed integral. A screw'BI, see Figure 2.k

is threaded into "the lower plate and'Y provided with a lock nut so that the spacing of the plates V25 and 2l, see Figure 5, may be adjusted.

The ears 3l! are engagedfby the rear Ylatch Z2 at one position in the operation of theV apparatus and are'so shown in Figur-e 2. The frontV latch Vhind which the fingers ofthe front latch 2i drop.

vFigure 6 shows a'detail of one of the latches, for example the rear latch 22,v the latches being substantially duplicates and being provided with downwardly extending tongues 33, see Figure 6, which are positioned on opposite sides of the guide rails i, as may be seen from Figure 2.

The bottom plate 27 of the auxiliary carriage 25 contacts the bracket I2, see Figure 2, the bracket l2 acting as a stop to limit the rearward motion of the auxiliary carriage.

The relatively heavy weight is attached to the chain 3d and the relatively lighter weight is attached to the chain or other member 35, the chain 35 passing over the front pulley 36 pivotally carried by a bracket and attached to the under side of the rails I, as shown in Figure 2,

the chain 35 extending to the main carriage, as shown in Figures 2 and 3. From the main carriage a chain 35 extends to a dash pot hereinafter described. A headed rod or bolt 3l passes through the ear 38 of the front bracket and is locked in place by a nut, as shown in Figures 2 and 3. front trip lever 39 which is provided with-an upwardly projecting arm it connected by means of,l a link fil with the rear trip member 52, such rear trip member being pivoted to the bracket I2 and being normally held in a retracted position by means of the spring 43, as shownin Figure 2. The operation, therefore, of these two trip members is simultaneous though in opposite directions, the rear trip member being adapted to trip the rear latch 22 and the front trip member being adapted to trip the front latch 2l when the front latch is locked `behind the catch 32. A pull rod M is provided and attached to the front trip member 3S and extends rearwardly through guiding ear |35 formed on the bracket I2, suitable stops Sii being provided on the rod to limit its motion in each direction, see Figuresl 2 and 3.

The rod is attached to the pullcord 41, see` Figure 1, and this pull cord extends rearwardly over the pulleyk 48, see Figures 1 and 14. The pullcord passes over a pulley t9 which carries a iiat weight 5B which is positioned, as may be seen in Figure 1, closely adjacent the rear wall 5I of the garage so asto prevent the pulley i9 from rocking out of its correct Vposition when the weight 55 is raised and lowered in a manner hereinafter to appear. The pulley 5.9 in reality is a sheave pulley and is provided with a contacting face 53 adapted'to'engage a stop 53 carried by the bracket 54 that supports the pulley 58, see Figure 14. A second pulley. 55 is also supported from theY bracket. From the second pul- This rod or bolt forms the axis of theV ley 55 thepull cord extends through a xed eyelet or pulley 55, see Figures Vl and 12, and

hangs downwardly, as shown in Figure l, andv is provided with a weighted end 51 'whchmay considerable amount of slack may be withdrawn,

as the weight 5G is merelyY lifted, seeFigure's 1 and 14. However, when the member 52 contacts the stop 53, the pull cord then becomestaut and rocks the trip members 3S and 42 to tripping position, theV trip members working simultaneously though in opposite directions as described,

and these trip members vwill trip the front or the rearlatch, as the case may be, to release the main carriage either from the front catchV 32 ner.

connected by means of a cord with a fixed.

ure 1, will be tightened and will takefup the slack, as shown lin Figure v1, a suitable weight 5S being provided t'o Vmaintain the Ahorizontal -portion of the chain 35 taut, 'the Yforward travel of the carriage iat 'the latter portion of its stroke being thereby Ireta'r'd'ed and thus retarding the nal opening motion of the doors to prevent shock or jar.

Additional means are provided for operating the 'trip Amechanism from the outside of the garage. This -means comprises a bowed spring '60, see Figures `1 and 11, which is held in spaced relation to the door 4 and is provided with a padded portion 6| adapte-d to be struck by the bumper of the car when it is desired to have the doors automatically open. The spring E0 is a very heavy spring and cannot be operated by a person pressing against it but can be operated by driving the bumper of the car against the spring. rIihe motion of the heavy leaf spring 1iii) is transmitted vby means of the rod 62, see Fig'- ure 1l, which extends through Athe 'door andris guided by a bracket '63. The end of the rod 52 has bolted thereto a bifurcated clip 64 into which a link of the chain 'G5 is secured. The chain is connected with Vthe cable '56, see Figures 1, Sand 11, and this 'cable connects with the bottom looped end of the rod 61, as shown most clearly in Figures 8 and 9.

VThe upper end of the rod is connected to an arm oi a 'bell crank lever 63, see particularly Figures 3 and y9, pivotally supported from the door 4 and this bell crank lever "is adapted to engage a pin or abutment A69 carried by the front trip member 39, as may be seen from Figures 3, 8 and 9, the iron't and rear trip members being of U-shape, as shown most clearly in Figure 3.

It is obvious, therefore, that when the spring Si) is pressed inwardly by means of the bumper of the car, that the rod 51 is pulled downwardly and the trip mechanism is operated. The rod El is provided with a looped .portion which'slants upwardly, as indicated at 'lil in Figures 8 and 10, which normally bears against the shank 'H ci an eyelet or headed member 'carried by the door; the rod is also provided with a horizontal portion 'l2 which extends through a loop or 'eyelet formed in a rod cr other member 13 connected to the `plunger of the door catch indicated generally at 14 in Figure 8, such vcatch locking the door in closed .position in the customary man'- The horizontal portion l2 of the rodl is member 4ifi carried by the frame work of the door, as shown in Figures `8 and 12. Additionally the rod 13 is connected to the arm 11 'of a key operated member, the shankr 13 of which, see Figure 7, is 'threaded into the door and provided with a slot 19 adapted to receive a 'correspondingly shaped key.

Obviously another type of mechanism could replace that shown in Figure 7 more on the order of a conventional lock if desired provided a movable portion of the lock is connected to the rod `ltrto withdraw the plunger 14 when the lock is released.

The relatively heavy and relatively light and the "driver desires to -unlock 1the doors, he merely inserts his "key, not `shown, in the slot T9 and rotatesthe arm 11, Seel-Figures 7 and 8, thus withdrawing theplun'ger of the latch 14 and allowing him to vopen the doors. However, the latch 14, see -Figure 8, is locked in retracted position vfor fthe horizontal lportion 12 of the rod B1 will slide 4beneath the member 1|, see Figures 8 and 10, and thus hold the latch in retracted position. However, as the doors coinplete their opening stroke, the cord 15 tightens and withdraws the horizontal portion 12 or locking portieri of the rod 61 from the member 'Il and releases the catch 14 so that it is again in condition to snap linto llocking position when the doors are closed, the latch 14 being the ordinary type of spring latch.

Motion of one door will cause simultaneous motion of the other door through the medium of the connecting rods or links 23 'and 24 and the main carriage, as 'is obvious from Figures 2, 3 vand 12. During this loperation the main carriage moves forwardly and pulls the auxiliary car-'ra'ge 25 with it, thus raising the Iheavy weight 89 and 4lowering the Slight weight 8l, the auxiliary car-riage lbeing 'temporarily attached to the main carriage by means of the rear latch 22 of the main carriage'see Figure '2. When the doors are completely opened, the fron`t=`1atch 2l of the main carriage, Ysee Figure 4, latches ove-r the catch 32 on the guide rails I -and thus locks the doors open. The driver -now lenters his car and drives from the garage. In passing out of the garage, he catches the pull cord 41, see Figure l,

.and holds this cord as the car moves from the garage. When all fthe slack in the :pull cord is taken up, the trip members 42 and 39 are simultaneously operated, though the trip member 42 performs n'o function at this time. The front trip member 39, however, lifts the front latch 2i of the main carriage from Vthe catch 32 and allows the heavyweight to pull the auxiliary carriage and main carriage rearwardly. This thus pulls the main carriage rearwardly and closes` the doors. AHowever, before the ldoors can close due to their inertia, it is obvious that the slack take up mechanism for the pull cord will have operated land the pull'cord is immediately drawn into thegar'age prior to the Aclosing ofthe doors. It is to be noted vthat the ordinary door latch 'lil is in condition to operate' and to thus lock the doors closed.

Upon returning to the garage, the driver causes the bumper of the automobile to strike the padded portion 63| of the leaf spring see Fig urell, thus pressing the plunger 'S2 inwardly and pulling the members 55 and Se downwardly, it being noted 'that a spring 65 is interposed between such members. This draws the rod 61 downwardly and causes the lbell crank lever see Figure 9, to 'mc-ve the trip 'members to tripping position. The iront trip member 3S, rsee Figure 2, performs no function at lthis time but the rear 'trip member '42 lifts the rear latch 22 of the main carriage from the auxiliary carriage and this allows the malin'carr'iage to move forwardly under the influence of thelight weight. The downward motion '-of the rod 61 also moves the rod 13 down".

wardly tand thus withdraws rthe spring catch 'lf-3 from door locking position. t is locked in this position due -to the fact that the horizontal portion 12 oi 'the vrod 61 has now passed rbeneath the member Tl, see lFigure l0. The forward ma tion Vor the main carriage opens the ldoor and as the ydoors near full v`open position, the chain 535 ist esY

' returns. Y

Additionally, it is to be noted that there is no chance of damage to the car due to the blowing is retarded by the' dash pot mechanism-58, see Figure l, thus retarding the nal opening motion of the doors. The front catch 2| now latches to the front latch 32, see Figure 4, and holds the doors open allowing the driver to drive the car into the garage. Thereafter the driver trips the trip mechanism through the medium of the pull cord and manually closes the doors.

In addition to the main functions hereinabove described, it is to be noted particularly that the force required to automatically open the door by delecting the heavy spring Si) may be adjusted by adjusting the pointat which the chain t5 hooks into the catch 54, see Figure l1.

It is obvious that if a considerable amount of slack is provided, that the leaf spring Sii has to travel through a considerable stroke to release the mechanism, whereas a tighter adjustment of the chain with less slack will require a lesser stroke Vof the relatively heavy leaf spring @0, under all conditions the spring 55 preventing breaking oi' the parts due to over travel of one with reference to the other.

It is to beunderstood that although the swinging type of garage door has been shown, it isy and second, for the automatic opening of the doors, so that after the driveris in his car within the garage, he does not have to alight from his car to operate the doors either `to close? them when he leaves the garage or to open them when he shut of the door while the driver isY entering or leaving the garage, as the doors are locked in openV position by the automatic mechanism. Additionally, whenever the doors are closed, they are Ylocked in closed position and itis obvious that'the ydoors may be unlocked from theoutside, as has been heretofore described, or from the inside of the garage by merely pulling downwardlycn the rod i3, see Figure 8.*

t will be seen that a relatively .simple me-V latter having been shown for the purpose of illustration.Y It is therefore intended that neither the word door nor the word doors is intended tcr limit the invention either'to a single door or to a pair'of doors.

It is to be noted particularly that the same of the garage. The mainbody of the device constitutes `a single unit Vwhich is shipped and installed as a unitary structure.

Although this invention has been described in considerable detail, it is `to be understood that Such description is intended Vas illustrative rather than limiting, as the invention may be variously embodied and is to be interrupted as claimed.

means to close said doors, means normally connecting said main carriage and said auxiliary carriage, and means for detaching said main carriage from said auxiliary carriage.

2. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage carried on said guiding means and operatively connected to said doors to open and close said doors as said carriage movesr forward and backward alongsaid guiding means, an auxiliary carriage carried on said guiding means, means temporarily connecting said auxiliary and main car-l riages, power means for moving said main carriage in a forward direction to open said doors, power means for moving said auxiliary carriage in the reverse direction with a greater force than said first power means to close said doors, de-` tachable latching means yfor locking said main and auxiliary carriages in their forward positions, and means for releasing said detachable latching means. f Y

3. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage carried on said guiding' means and operatively connected to said doors to open and close said doors as said carriage moves forward and-backward along said guiding means, an auxiliary carriage carried on said guiding means, means temporarily connecting said auxiliary and main carriages, power means for moving said main carriage lin a forward-direction to open said doors, f

power means for moving said auxiliary carriage in the reverse direction with a greater force than Ysaid rst power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, means forY releasingV said detachable latching vmeans, and means for detaching said main carriage from said auxiliary carriage when said car-` riagesY are at the rear endof their strokes.

connected to said doors to open and close said doors as-s'aid carriagemoves forward and backward along said guiding means, an auxiliary carriage carried on said guiding means, means temporarily connectingV said auxiliary and Vmain carriages, power meansfor moving said main carriage in aforward direction to open said doors, power means for moving said auxiliary carriage in theV reverse direction with a greater force than said iirst power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, means for releasing said detachable latching means, and bumper means operable from an automobile and mounted exteriorly of said doorfsy carried on said guiding means and operatively `connected to said doors t open and close said doors as said carriage moves forward and backward along said guiding means, an auxiliary carriage carried on said guiding means, means temporarily connecting said auxiliary and main carriages power means for moving said main carriage in a forward direction to open said doors, power means for moving said auxiliary carriage in the reverse direction with a greater force than said first power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, means for releasing said detchable latching means, and bumper means operable from an automobile and mounted exteriorly of said doors for detaching said main carriage from said auxiliary carriage when said carriages are at the rear ends of their strokes, said bumper means being adjustable to vary the force required to disconnect said main carriage from said auxiliary carriage.

6. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage carried on said guiding means and operatively connected to said doors to open and close said doors as said carriage moves forward and backward along said guiding means, an auxiliary carriage carried on said guiding means, means temporarily connecting said auxiliary and main carriages, power means for moving said main carriage in a forward direction to open said doors, power means for moving said auxiliary carriage in the reverse direction with a Vgreater force than said rst power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, means for releasing saidI detachable latching means, door locking Vmeans for locking said doors in closed position, and means for simultaneously releasing said door locking means and detaching said main car-riage from said auxiliary carriage.

7. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage carried on said guiding means and operatively connected to said doors to open and close said doors as said carriage moves forward and backward along said guiding means, an auxiliary carriage carried on said vguiding means, means temporarily connecting said auxiliary and main carriages, power means for moving said main carriage in a forward direction to open said doors, power means for moving said auxiliary carriage in the reverse direction with a greater force than said first power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, door locking means for locking said doors in closed position, means for simultaneously releasing said door locking means and detaching said main carriage from said auxiliary carriage, and pull cord means operable exteriorly of said doors when said doors are open for releasing thedetachable latching means, whereby said carriages will move rearwardly to close said doors.

8. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage carried on said guiding-means and operatively conencted to said doors4 to Yopen and close said doors as said carriage moves forward and backward along said -guiding means, an auxiliary carriage carried o n said guiding means, means ternporarily connecting said auxiliary and main carriages, power means for moving said main carriage in a forward direction to open said doors,

power means for moving said auxiliary carriage in the reverse direction with a greater force than said first power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, door locking means for locking said doors in closed position, means for simultaneously releasing said door locking means and detaching said main carriage from said auxiliary carriage, and pull cord means operable exteriorly of said doors when said doors are open for releasing the detachable latching means, whereby said carriages will move rearwardly to close said doors, said pull cord means including means for providing slack in the pull cord for allowing the pull cord to. be drawn a material distance from the doors before said pull cord means operates and for taking up the, slack before the doors close. 9. In a device of the class described, a garage, said garage having doors, door closing means including power means for storing power when said doors are manually opened, latching means for temporarily locking said doors open, pull cord means for releasing said latching means, said pull cord means including a p-ull cord and slack take up. means for preventing the release of said latching means until the slack has been removed from said pull cord, whereby said pull cord may be operated by the driver of an automobile while said automobile moves outwardly clear of said doors, said slack take up means retracting said pull cord Within said garage upon the release of said pull cord prior to the closing of said doors. l0. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage carried on said guiding means and operatively connected to said doors tov open and close said doors as said carriage moves forward and backward along said guiding means, an auxiliary carriage carriedon said guiding means, means temporarily connecting said auxiliary and main carriages, power means for moving said main carriage in a forward direction to open said doors, power means for moving said auxiliary carriage in the reverse direction with a greater force than said first power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, dash pot means for delaying the final opening motion of said doors, and means for releasing said detachable latching means.

ll. In a doorA opening and closing mechanism, a pair of doors, guiding means, a main carriage carried on said guiding means and operatively connected to said doors to open and close said doors as said carriage moves forward and backward along said guiding means, an auxiliary carriage carried on said guiding means, means temporarily connecting said auxiliary and main carriages, power means for moving said main carriage in a forward direction to open said doors, power means for moving said auxiliary carriage in the reverse direction with a greater force than said iirst'power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, door locking means for locking said doors'closed, and means operable by an. automobile externally of said doors for detaching said main carriage Afrom said auxiliary carriage and forY releasing saiddoor locking means. Y l2. In a door openingA and closing mechanism, a pair of doors, guiding means, a main carriage carried on said guiding means and operatively connected to said doors to open and close said doors as said carriage moves forward and backward along said guiding means, an auxiliary carriage carried on said guiding means, means temporarily connecting said auxiliary and main carriages, power means for moving said main carriage in a forward direction to open said doors, power means for moving said auxiliary carriage in the reverse direction with a greater f'orce than said first power means to close said doors, detachab-le latching means for locking said main and auxiliary carriage in their forward positions, door locking means for locking said doors closed, means operable by an automobile externally of said doors for detaching said main carriage from said auxiliary carriage and for releasing said door locking means, and means for holding said door locking means in released position during the initial opening motion of said doors and for releasing said door locking means during the final opening motion of said doors.

13. In a door opening and closing mechanism, al pair of doors, guiding means, a main carriage carried on said guiding means and operatively connected to said doors to open and close said vdoors as said carriage moves forward and backward along said guiding means, an auxiliary carriage carried on said guiding means, means temporarily connecting said auxiliary and main carriages, power means for moving said main carriage in a forward direction to open said doors, power means for moving said auxiliary carriage v in the reverse direction with a greater force than said first power means to close said doors, detachable latching means for locking said main and auxiliary carriages in their forward positions, means for releasing said detachable latching means, and suspension means and lateral adjustment means for supporting and laterally adjusting said guiding means.

14. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage guided by said guiding means, a pair of links extending from said main carriage to said doors for opening said doors when said main carriage moves forwardly and for closing said doors when said main carriage moves backwardly, an auxiliary carriage guided by said guiding means, a first latching means carried by said main carriage for, temporarily engaging said auxiliary carriage to temporarily lock said carriages together, power means for moving said main carriage in a forward direction, power means for moving said auxiliary carriage in a rearward direction with a greater force than said first power means, a second latching means carried by said main carriage for locking said main carriage in its forward position, and tripping means for selectively tripping said first and second mentioned latching means,

15. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage guided by said .guiding means, a pair of links extending from said main carriage to said doors for opening said 1doors when said main carriage moves forwardly and for closing said doors when said main carriage moves backwardly, an auxiliary carriage guided by said guiding means, a first latching means carried by said main carriage for temporarily engaging said auxiliary carriage to temporarily lock said carriages together, power means for moving said main carriage in a forward direction, power means for moving said auxiliary carriage in a rearward direction with a greater force than said first power means, a sec- 'ond latching means carried by said main carriage for locking said main carriage in its forward position, pull cord means for releasing said second latching means, and means carried by and externally of said doors for releasing said rst mentioned latching means.

16. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage guided by said guiding means, a pair of links extending from said main carriage to said doors for opening said vdoors when said main carriage moves forwardly and for closing said doors when said main carriage moves backwardly, an auxiliary carriage guided by said guiding means, a first latching means carried by said main carriage for temporarily engaging said auxiliary carriage to temporarily lock said carriages together, power means for moving said main carriage in a forward direction, power means for moving said auxiliary carriage in a rearward direction with a greater force than said first power means, a sec- .ond latching means carried by said main carriage for locking said main carriage in its forward position, pull cord means including a pull cord adapted to be drawn outwardly past said doors when said doors are open for tripping said second latching means and including pull cord retracting means for retracting said pull cord prior to the closing of said doors, and bumper means adapted to be actuated by an automobile for releasing said rst mentioned latching means.

1'7. In a door opening and closing mechanism, a pair of doors, guiding means, a main carriage carried by said guiding means, links connecting said main carriage with said doors to open said doors when said main carriage moves forwardly Y and to close said doors when said main carriage moves rearwardly, an auxiliary carriage carried by said guiding means, said main carriage having a rst latch means for temporarily engaging said auxiliary carriage and having a second latch means for locking said main carriage and said auxiliary carriage in a forward position, simultaneously operable tripping means carried by said guiding means for tripping said first latch means when said main carriage is in its rear position and for tripping said second latch means when said main carriage is in its forward position, and means for operating said tripping means.

18. In a door opening and closing mechanism, at least one door, guiding means, a carriage carried on said guiding means and operatively connected to said door to vopen and close said door as said carriage moves back and forth along said guiding means, power means for moving said carriage back and forth along saidrguiding means, latching means for latching said carriage against rearward door closing motion, a pull cord havin-g one end connected to said latching means and having the other end constituting a manipulating end and normally hanging down adjacent and inwardly of said door, and quick operating slack take-up means for said pull cord comprising a weighted pulley over Vwhich said pull cord is looped, whereby the manipulating end of said pull cord may be grasped byy the operator and drawn outwardly a material distance while the` door is open to trip said latching means and whereby upon release of said pull cord said pull cord will be retracted prior to the closingof said door.

FRED LICI-ITFELDT. 

